METTL5 promotes gastric cancer progression via sphingomyelin metabolism

BACKGROUND The treatment of gastric cancer(GC)has caused an enormous social burden worldwide.Accumulating studies have reported that N6-methyladenosine(m6A)is closely related to tumor progression.METTL5 is a m6A methyltransferase that plays a pivotal role in maintaining the metabolic stability of cells.However,its aberrant regulation in GC has not been fully elucidated.AIM To excavate the role of METTL5 in the development of GC.METHODS METTL5 expression and clinicopathological characteristics were analyzed via The Cancer Genome Atlas dataset and further verified via immunohistochemistry,western blotting and real-time quantitative polymerase chain reaction in tissue microarrays and clinical samples.The tumor-promoting effect of METTL5 on HGC-27 and AGS cells was explored in vitro by Cell Counting Kit-8 assays,colony formation assays,scratch healing assays,transwell assays and flow cytometry.The tumor-promoting role of METTL5 in vivo was evaluated in a xenograft tumor model.The EpiQuik m6A RNA Methylation Quantification Kit was used for m6A quantification.Next,liquid chromatography-mass spectrometry was used to evaluate the association between METTL5 and sphingomyelin metabolism,which was confirmed by Enzyme-linked immunosorbent assay and rescue tests.In addition,we investigated whether METTL5 affects the sensitivity of GC cells to cisplatin via colony formation and transwell experiments.RESULTS Our research revealed substantial upregulation of METTL5,which suggested a poor prognosis of GC patients.Increased METTL5 expression indicated distant lymph node metastasis,advanced cancer stage and pathological grade.An increased level of METTL5 correlated with a high degree of m6A methylation.METTL5 markedly promotes the proliferation,migration,and invasion of GC cells in vitro.METTL5 also promotes the growth of GC in animal models.METTL5 knockdown resulted in significant changes in sphingomyelin metabolism,which implies that METTL5 may impact the development of GC via sphingomyelin metabolism.In addition,high METTL5 expression led to cisplatin resistance.CONCLUSION METTL5 was found to be an oncogenic driver of GC and may be a new target for therapy since it facilitates GC carcinogenesis through sphingomyelin metabolism and cisplatin resistance.

Targeting methyltransferase-like 5-mediated sphingomyelin metabolism:A novel therapeutic approach in gastric cancer

Gastric cancer(GC)is a global health problem and a leading cause of cancerrelated deaths,with its mortality rate ranking third among all cancers.The etiology and progression of GC are characterized by a complex interplay of genetic and epigenetic changes,which present challenges for its early diagnosis and effective treatment.Elucidating the mechanisms underlying the occurrence and development of GC and identifying novel biomarkers for early detection and prognosis are crucial to improving patient outcomes.This editorial examines the role of methyltransferase-like 5(METTL5)in the progression of GC through sphingomyelin metabolism by considering an article published by Zhang et al in the World Journal of Gastrointestinal Oncology in 2024,which is entitled“METTL5 promotes GC progression via sphingomyelin metabolism”.These authors investigated the biological behavior of METTL5 in GC by examining its expression patterns,clinical relevance,functional effect,and potential mechanisms,as well as its response to chemotherapy.This editorial provides valuable insights into the role of METTL5 in the progression of GC and its potential as a therapeutic target.

The relationship among amyloid-βdeposition,sphingomyelin level,and the expression and function of P-glycoprotein in Alzheimer’s disease pathological process

In Alzheimer’s disease,the transporter P-glycoprotein is responsible for the clearance of amyloid-βin the brain.Amyloid-βcorrelates with the sphingomyelin metabolism,and sphingomyelin participates in the regulation of P-glycoprotein.The amyloid cascade hypothesis describes amyloid-βas the central cause of Alzheimer’s disease neuropathology.Better understanding of the change of P-glycoprotein and sphingomyelin along with amyloid-βand their potential association in the pathological process of Alzheimer’s disease is critical.Herein,we found that the expression of P-glycoprotein in APP/PS1 mice tended to increase with age and was significantly higher at 9 and 12 months of age than that in wild-type mice at comparable age.The functionality of P-glycoprotein of APP/PS1 mice did not change with age but was significantly lower than that of wild-type mice at 12 months of age.Decreased sphingomyelin levels,increased ceramide levels,and the increased expression and activity of neutral sphingomyelinase 1 were observed in APP/PS1 mice at 9 and 12 months of age compared with the levels in wild-type mice.Similar results were observed in the Alzheimer’s disease mouse model induced by intracerebroventricular injection of amyloid-β1-42 and human cerebral microvascular endothelial cells treated with amyloid-β1-42.In human cerebral microvascular endothelial cells,neutral sphingomyelinase 1 inhibitor interfered with the changes of sphingomyelin metabolism and P-glycoprotein expression and functionality caused by amyloid-β1-42 treatment.Neutral sphingomyelinase 1 regulated the expression and functionality of P-glycoprotein and the levels of sphingomyelin and ceramide.Together,these findings indicate that neutral sphingomyelinase 1 regulates the expression and function of P-glycoprotein via the sphingomyelin/ceramide pathway.These studies may serve as new pursuits for the development of anti-Alzheimer’s disease drugs.

Alkaline sphingomyelinase(NPP7) in hepatobiliary diseases: A field that needs to be closely studied

Alkaline sphingomyelinase cleaves phosphocholine from sphingomyelin, platelet-activating factor, lysophosphatidylcholine, and less effectively phosphatidyl-choline. The enzyme shares no structure similarities with acid or neutral sphingomyelinase but belongs to ectonucleotide pyrophosphatase/phosphodiesterase(NPP) family and therefore is also called NPP7 nowadays. The enzyme is expressed in the intestinal mucosa in many species and additionally in human liver. The enzyme in the intestinal tract has been extensively studied but not that in human liver. Studies on intestinal alkaline sphingomyelinase show that it inhibits colonic tumorigenesis and inflammation, hydrolyses dietary sphingomyelin, and stimulates cholesterol absorption. The review aims to summarize the current knowledge on liver alkaline sphingomyelinase in human and strengthen the necessity for close study on this unique human enzyme in hepatobiliary diseases.

FT-Raman Spectroscopic Studies on the Interaction of Metal Ions With Sphingomyelin Bilayer

The interaction of trivalent lanthanide ions and divalent calcium ions with sph-'ngomyelm bilayer has been studied by FT-Raman spectroscopy.The results showed that the bonding of metal ions to the phosphate group of sphingomyelin bi-iayer,either La3+or Ca2+did not change the conformation of the choline group,that is,O-C-C-N+is still in its gauche conformation.The presence of metal ions changed the states of the interfacial region from liquid-like to amorphous state and even to crystalline.They increased the fluidity of acyl chains of sphingomyelin bilaver and made them packed disorderly.

Sphingomyelin synthase activity measurement by the fluorescent product in cell culture medium or animal plasma

Sphingolipids, a new class of lipid mediators, are involved in a variety of important physiological and pathological processes. Sphingomyelin synthase （SMS） is an enzyme to convert the ceramide （Cer.） and phosphatidylcholine into sphingomyelin （SM） and diacylglycerol, which plays a key role in sphingolipid biosynthesis. Two SMS isoforms, SMS1 and SMS2, have been identified with different subceUular localizations and expression level in tissues. Previous studies have shown that SMS may serve as a potential therapeutic target for the treatment of various diseases, such as cardiovascular and metabolic diseases. Thus, there is an urgent need for a rapid and sensitive method for SMS activity analysis. In our study, we developed a novel method for SMS activity by monitoring the appearance of the product, NBD-SM, in the tissue culture medium or blood and applied this method in cells and mice. In Huh7 cells, the interassay coefficient of variation of the SMS activity assay was （3.60±0.07）% . In wild type （WT） mice, we observed accumulation of NBD-SM in blood in a time dependent fashion. In SMS2 KO mice, NBD-SM in plasma collected at 5- （0%, P〈0.01）, 30- （16%, P〈0.01）, and 60 min （21%, P〈0.01） after injection of fluorescence liposome solution was significantly decreased compared with WT mice. However, in SMS1 KO mice, NBD-SM in plasma collected 5- and 30 min is similar to that in WT mice. Our results suggest that this method could be used for SMS activity measurement in vitro and in vivo.

磷脂分子调控畜禽肉品质研究进展

磷脂是一类结构复杂、功能多元的极性脂质分子,包括甘油磷脂和鞘磷脂2类。作为细胞膜的重要组成部分,磷脂分子参与生命体细胞信号传导、脂滴形成、细胞凋亡等多种生理活动,磷脂分子的代谢、水解及氧化赋予肉类食品独特的质地、风味和营养品质。磷脂分子的功能特性因其连接的极性基团和sn-1/sn-2位点脂肪酸种类不同而有所差异,脂质组学为磷脂分子结构确证与表征提供了强大技术支撑。本文介绍了肌内磷脂分子的结构与功能、检测及分析方法,重点综述了磷脂分子参与畜禽肉肌内脂肪沉积、调控宰后生鲜肉品质及加工肉制品品质的研究进展,以期为精准调控畜禽肉品质提供参考借鉴。

雷公藤甲素调控nSMase2-Cer鞘脂代谢信号通路发挥抗胰腺癌的作用及其相关机制研究

目的探究雷公藤甲素抑制胰腺癌细胞系PANC-1细胞增殖的作用机制,揭示其抗胰腺癌的作用与神经鞘脂之间的相互联系。方法用不同浓度梯度的雷公藤甲素处理胰腺癌PANC-1细胞后,检测细胞增殖、迁移能力及凋亡情况。通过PCR array实验筛选给药后PANC-1细胞上有变化的神经鞘脂基因,并通过q-PCR和Western blot实验验证所筛选基因的转录翻译情况。构建PANC-1细胞相关基因的过表达模型并进行细胞功能性实验验证。Western blot实验检测瞬时转染的PANC-1细胞给药前后及不同药物浓度下nSMase2蛋白水平的变化及Caspase-3蛋白水平的变化。免疫荧光实验检测不同药物梯度和过表达模型下神经酰胺(Cer)含量的变化。建立BALB/C裸鼠PANC-1皮下成瘤模型,在体内验证雷公藤甲素对裸鼠肿瘤大小的影响。提取肿瘤组织进行Western blot实验,肝组织进行HE染色实验。结果雷公藤甲素呈浓度梯度抑制PANC-1细胞的增殖、迁移能力并促进细胞凋亡。神经鞘脂相关基因SMPD3与雷公藤甲素抑制PANC-1细胞活力相关性最强,且雷公藤甲素可下调其在PANC-1细胞中的表达。过表达SMPD3后PANC-1细胞增殖、迁移能力明显增强,细胞凋亡减少。雷公藤甲素可促使PANC-1细胞内Cer含量的升高,而过表达SMPD3后是可以降低PANC-1细胞内Cer的含量,此外,雷公藤甲素还能够促进PANC-1细胞Caspase家族蛋白Caspase-3表达的上调。体内实验表明雷公藤甲素能够下调SMPD3蛋白的表达,促进Caspase-3活化进而促进肿瘤发生细胞凋亡,发挥抑制裸鼠体内肿瘤生长的作用。结论体内外实验均表明雷公藤甲素通过下调SMPD3的表达,影响nSMase2-Cer信号通路抑制PANC-1细胞的生长。

Ordering effects of cholesterol on sphingomyelin monolayers investigated by high-resolution broadband sum-frequency generation vibrational spectroscopy

This report investigated the ordering of the alky chain of sphingomyelin （SMs） monolayers induced by cholesterol at the air/water interface using high-resolution broadband sum frequency generation vibrational spectroscopy （HR-BB-SFG-VS）. The SFG spectra of the three nature sphingomyelin/cholesterol mixture monolayers with two concentrations of the cholesterol at the air/water interface are performed under different polarization combination. A new resolved CH2 symmetric stretching （d＋, ~2834 cm-1） and the CH3 symmetric stretching （r＋, ~2874 cm-1） mode are applied to characterize the conformational order in the sphingomyelin/cholesterol mixture monolayers. It was found that the cholesterol make the sphingosine backbones more conformational order. During this process, the conformational order of the N-linked acyl chain remains unaltered. Moreover, the sphingosine backbones of SMs have much larger contributions to gauche defects of SMs than one in the N-linked acyl chain. These results presented here not only shed lights on understanding of the interactions of sphingomyelin molecules with cholesterol molecules at interface but also demonstrates the ability of HR-BB-SFG to probe such complicated molecular systems.

鞘磷脂合成酶2通过Wnt/β-catenin通路调控卵巢癌TOV-21G细胞的恶性生物学行为

目的:探讨鞘磷脂合成酶2(SMS2)是否通过Wnt/β-catenin信号通路调控卵巢癌(OC)TOV-21G细胞增殖、迁移、侵袭、凋亡及其机制。方法:收集武汉市第三医院2022年7月至2023年5月间确诊的21例OC患者的癌及癌旁组织标本,免疫组化法检测OC组织SMS2表达水平。体外培养TOV-21G细胞,将细胞分为对照组、shRNA慢病毒阴性对照组(sh-NC组)、SMS2 shRNA慢病毒组(sh-SMS2组)、Wnt/β-catenin通路激活剂组LiCl(LiCl组)和sh-SMS2+LiCl组。Edu染色法、Transwell法、流式细胞术分别检测各组细胞的增殖、迁移和侵袭能力及凋亡水平,WB法检测细胞中SMS2、Ki67、cyclin D1、BAX、c-caspase3、Bcl-2及Wnt/β-catenin通路蛋白(β-catenin、c-Myc、MMP-9)的表达。构建TOV-21G细胞裸鼠移植瘤模型,观察敲低SMS2对移植瘤生长和SMS2、β-catenin表达的影响。结果:与癌旁组织比较,OC组织中SMS2呈高表达(P<0.01)。转染sh-SMS2后,TOV-21G细胞中SMS2表达水平显著降低(P<0.05),细胞的增殖、迁移和侵袭能力及Bcl-2、β-catenin、c-Myc、MMP-9蛋白表达均显著降低(均P<0.05),细胞凋亡率、BAX、c-caspase3蛋白表达均显著升高(均P<0.05);LiCl处理能逆转敲低SMS2对TOV-21G细胞增殖、迁移和侵袭及Wnt/β-catenin通路的抑制作用(均P<0.05)。体内成瘤实验显示,敲低SMS2抑制裸鼠移植瘤的生长及SMS2、β-catenin蛋白的表达(均P<0.05)。结论:敲低SMS2表达通过Wnt/β-catenin信号通路抑制OC TOV-21G细胞的增殖、迁移、侵袭并促进细胞凋亡,同时LiCl处理则能逆转敲低SMS2对TOV-21G细胞增殖、迁移和侵袭的抑制作用。

成年女性抑郁症患者血浆鞘磷脂组成特点与抑郁症状的相关性分析

目的分析成年女性抑郁症患者血浆鞘磷脂(SM)组成特点与抑郁症状的相关性。方法选取2020年5月至2021年3月我院收治的28例女性抑郁症患者作为观察组,同期招募25名健康女性作为对照组。采用汉密尔顿抑郁量表(HAMD)、汉密尔顿焦虑量表(HAMA)评估抑郁、焦虑严重程度,采用液相色谱-质谱联用技术(LC-MS)检测血浆中SM水平,分析SM组成特点与抑郁症状的相关性。结果观察组的HAMD、HAMA评分高于对照组(P<0.001)。观察组的SM总量水平显著低于对照组(P=0.018)。观察组的SM(t40∶1)+HCOO、SM(d40∶0)+H、SM(d36∶4)+H、SM(d30∶2)+H水平显著低于对照组(P<0.05)。Spearman相关性分析结果显示,SM差异分子与HAMA、HAMD评分呈负相关(P<0.05)。受试者工作特征(ROC)曲线结果显示,SM(d40∶0)+H、SM(t40∶1)+HCOO、SM(d36∶4)+H、SM(d30∶2)+H的曲线下面积(AUC)分别为0.903、0.807、0.803、0.727。结论抑郁症患者的血浆SM组成特点与抑郁症状呈负相关,SM(d40∶0)+H、SM(t40∶1)+HCOO、SM(d36∶4)+H、SM(d30∶2)+H分子可能是诊断女性抑郁症的潜在生物学标志物。

Design, Synthesis, and Biological Evaluation of Novel Dual Inhibitors of Secretory Phospholipase A2 and Sphingomyelin Synthase

A novel series of eight SMS and sPLA2 dual inhibitors containing indole and a-amino cyanide fragments of different length and substitution position was synthesized and evaluated by three different in vitro assays. Biological evaluation showed that all compounds provided inhibitory effects against SMS （about 50% inhibition at 100 μmol/L） and sPLA2 （14-32 μmol/L）. All the compounds had the SMS activity better than the positive control compound D609 in SMS2 homogenate, with compounds 5b and fie ideal for liver homogenate and SMS2 high expression cell homogenate, respectively.

Molecular Modeling of the Three-Dimensional Structure of Human Sphingomyelin Synthase

Sphingomyelin synthase （SMS） produces sphingomyelin and diacylglycerol from ceramide and phosphatidyl- choline. It plays an important role in cell survival and apoptosis, inflammation, and lipid homeostasis, and therefore has been noticed in recent years as a novel potential drug target. In this study, we combined homology modeling, molecular docking, molecular dynamics simulation, and normal mode analysis to derive a three-dimensional struc- ture of human sphingomyelin synthase （hSMS 1） in complex with sphingomyelin. Our model provides a reasonable explanation on the catalytic mechanism of hSMS 1. It can also explain the high selectivity of hSMS 1 towards phos- phocholine and sphingomyelin as well as some other known experimental results about hSMS1. Moreover, we also derived a complex model of D609, the only known small-molecule inhibitor of hSMS 1 so far. Our hSMS 1 model may serve as a reasonable structural basis for the discovery of more effective small-molecule inhibitors of hSMS 1.

Effects of metal ions on the conformation of polar headgroup of sphingomyelin bilayer

With the wide application of rare earth in agriculture, medicament, especially theapplication of Gd-DTPA as nuclear magnetic resonance image reagent in clinical prac-tice, the studies on the toxicology in biological body, as well as the study on the use asinformative probes instead of divalent calcium ion in biological and biochemical researchhave attracted intensive concern.

肾虚肝郁型多囊卵巢综合征患者LncRNA SRA和鞘磷脂的表达及其对疾病的诊断意义

目的:探讨肾虚肝郁型多囊卵巢综合征(PCOS)患者与正常对照组患者的临床特征及血清LncRNA SRA和鞘磷脂(SM)水平的差异。方法:纳入30例肾虚肝郁型PCOS妇女作为病例组,30例正常的妇女作为对照组,测定临床指标和血清LncRNA SRA、SM水平,应用SPSS软件进行数据统计分析。结果:肾虚肝郁型PCOS患者T、DHEAS、GS、LncRNA SRA、SM、LH、PRL、E_(2)、AND、CHO、FAI、LH/FSH等水平明显高于对照组(P<0.05);LncRNA SRA的ROC曲线下面积(AUC)为0.733,敏感性和特异性分别为70%和73%。SM的AUC为0.691,敏感性和特异性分别为57%和80%。结论:肾虚肝郁型PCOS患者血清中LncRNA SRA和SM水平增高,LncRNA SRA和SM水平可以作为肾虚肝郁型PCOS的诊断标志物,为肾虚肝郁型PCOS疾病的诊断提供依据,同时可以为PCOS的药物治疗提供靶点。

Substance P promotes epidural fibrosis via induction of type 2 macrophages

In response to spinal surgery,neurons secrete a large amount of substance P into the epidural area.Substance P is involved in macrophage differentiation and fibrotic disease.However,the specific roles and mechanisms of substance P in epidural fibrosis remain unclear.In this study,we established a mouse model of L1–L3 laminectomy and found that dorsal root ganglion neurons and the macrophages infiltrating into the wound area released sphingolipids.In vitro experiments revealed that type 1 macrophages secreted substance P,which promoted differentiation of type 1 macrophages towards a type 2 phenotype.High-throughput mRNA-seq analysis revealed that the sphingolipid metabolic pathway may be involved in the regulation of type 2 macrophages by substance P.Specifically,sphingomyelin synthase 2,a component of the sphingolipid metabolic pathway,promoted M2 differentiation in substance P-treated macrophages,while treating the macrophages with LY93,a sphingomyelin synthase 2 inhibitor,suppressed M2 differentiation.In addition,substance P promoted the formation of neutrophil extracellular traps,which further boosted M2 differentiation.Blocking substance P with the neurokinin receptor 1 inhibitor RP67580 decreased the number of M2 macrophages in the wound area after spinal surgery and alleviated epidural fibrosis,as evidenced by decreased fibronectin,α-smooth muscle actin,and collagen I in the scar tissue.These results demonstrated that substance P promotes M2 macrophage differentiation in epidural fibrosis via sphingomyelin synthase 2 and neutrophil extracellular traps.These findings provide a novel strategy for the treatment of epidural fibrosis.

A novel mutation in ROR2 led to the loss of function of ROR2 and inhibited the osteogenic differentiation capability of bone marrow mesenchymal stem cells(BMSCs)

Receptor tyrosine kinase-like orphan receptor 2(ROR2)has a vital role in osteogenesis.However,the mechanism underlying the regulation of ROR2 in osteogenic differentiation is still poorly comprehended.A previous study by our research group showed that a novel compound heterozygous ROR2 variation accounted for the autosomal recessive Robinow syndrome(ARRS).This study attempted to explore the impact of the ROR2:c.904C>T variant specifically on the osteogenic differentiation of BMSCs.Methods:Coimmunoprecipitation(CoIP)-western blotting was carried out to identify the interaction between ROR2 and Wnt5a.Double-immunofluorescence staining was used for determining the expressions and co-localization of ROR2 and Wnt5a in bone marrow mesenchymal stem cells(BMSCs).Western blot(WB)analysis and quantitative reverse transcription polymerase chain reaction(RT-qPCR)were conducted to identify the expression levels of ROR2 in the BMSCs transfected with LV-shROR2 or LV-ROR2-c.904C>T.The alkaline phosphatase(ALP)activity was detected,and Alizarin Red S staining was done for evaluating the osteogenic differentiation of BMSCs.RT-qPCR was employed to identify the expression of the sphingomyelin synthase 1(SMS1)mRNA in the BMSCs transfected with LV-shROR2 or LV-ROR2-c.904C>T and the mRNA expression levels of Runt-related transcription factor 2(RUNX2),osteocalcin(OCN),and osteopontin(OPN).WB was performed to confirm the protein expressions of extracellular regulated protein kinases1(ERK),P-ERK,Smad family member1/5/8(Smad1/5/8),P-Smad1/5/8,P-P38,P38,RUNX2,OCN,and OPN in the BMSCs transfected with LV-shROR2/LV-ROR2-c.904C>T and sphingomyelin(SM).Results:The ROR2:c.904C>T mutant altered the subcellular localization of the ROR2 protein,which caused an impaired interaction between ROR2 and Wnt5a.The depletion of ROR2 restricted the osteogenic differentiation capability of BMSCs and downregulated the expression of SMS1.SM treatment could reverse the inhibition of osteoblastic differentiation in ROR2-depleted BMSCs.Conclusion:The findings of this work revealed that the ROR2:c.904C>T variant led to the loss of function of ROR2,which impaired the interaction between ROR2 and Wnt5a and also controlled the osteogenic differentiation capability of BMSCs.Furthermore,SM was revealed to be engaged in the osteoblastic differentiation of BMSCs regulated by ROR2,which renders SM a potential target in the therapy for ARRS.

神经酰胺在炎症反应及相关疾病中的作用研究进展

神经酰胺是鞘磷脂信号通路代谢的中心分子,可参与调控细胞增殖、分化、衰老和凋亡等细胞生命活动及多种炎症反应。神经酰胺的合成主要有从头合成途径、鞘磷脂代谢途径和补救途径,其代谢途径主要涉及神经酰胺酶和神经酰胺激酶。神经酰胺与多种炎症相关性疾病的发生发展关系密切,如慢性阻塞性肺疾病、类风湿性关节炎、炎症性肠病、多发性硬化症和阿尔茨海默病等。本文主要综述神经酰胺与不同炎症相关性疾病发生发展的关系,旨在为炎症相关疾病的防治提供新的思路。

Ceramide is involved in alcohol-induced neural proliferation

Prenatal alcohol exposure, especially during early pregnancy, can lead to fetal alcohol syndrome. The pharmacological and toxicological mechanisms of ethanol are related to the effects of ceramide In this study, we established an alcohol exposure model in wild-type mice and in knockout mice for the key enzyme involved in ceramide metabolism, sphingomyelin synthase 2. This model received daily intragastric administration of 25% ethanol, and pups were used at postnatal days 0, 7, 14, 30 for experiments. Serology and immunofluorescence staining found that ethanol exposure dose-dependently reduced blood sphingomyelin levels in two genotypes of pups, and increased neural cell proliferation and the number of new neurons in the hippocampal dentate gyrus. Western blot analysis showed that the relative expression level of protein kinase C e increased in two genotypes of pups after ethanol exposure. Compared with witd-type pups, the expression level of the important activator protein of the ceramide/ceramide-l-phosphate pathway, protein kinase C a, was reduced in the hippocampus of sphingomyelin synthase 2 knockouts. Our findings illustrate that ceramide is involved in alcohol-induced neural proliferation in the hippocampal dentate gyrus of pups after prenatal ethanol exposure, and the mechanism may be associated with increased ex- pression of protein kinase C a activating the ceramide/ceramide-l-phosphate pathway.

艾司氯胺酮对慢性可变应激小鼠抑郁样行为及前额叶皮质鞘脂水平的影响

目的 探讨艾司氯胺酮对慢性可变应激(CVS)小鼠抑郁样行为及前额叶皮质(PFC)鞘脂水平的影响。方法 将31只C57小鼠随机分为对照组(n=10)、模型+生理盐水组(n=10)和模型+艾司氯胺酮治疗组(n=11)。模型+生理盐水组和模型+艾司氯胺酮治疗组小鼠均接受21 d CVS造模。造模结束后,两组小鼠分别接受10μL/g生理盐水、10 mg/kg艾司氯胺酮腹腔注射。通过旷场实验、高架十字迷宫测试、悬尾实验及强迫游泳实验测试小鼠的抑郁样行为;随后处死小鼠,分离出PFC,通过高效液相色谱-质谱联用技术检测PFC鞘脂水平及组成小分子差异,采用LipidSearch 4.1和SIMCA-P 14.1软件分析脂质相对含量。使用SPSS 26.0进行数据处理,多组间差异采用单因素方差分析,两组间差异进行Tukey检验。结果 (1)CVS模型可以诱导稳定的小鼠抑郁样行为,3组小鼠旷场测试、高架十字迷宫测试、悬尾实验及强迫游泳测试的结果均有统计学差异;单次腹腔注射艾司氯胺酮可以逆转小鼠抑郁样行为,并且改变部分鞘脂水平及其组成小分子。(2) 3组小鼠鞘脂总体水平的差异有统计学意义(F_(2,28)=22.92,P<0.01),鞘脂的三个亚类鞘磷脂(F_(2,28)=15.76,P<0.01)、脑苷脂(F_(2,28)=21.56,P<0.01)、神经节苷脂(F_(2,28)=4.056,P<0.05)之间的差异均有统计学意义。进一步对其小分子组成进行分析发现,CVS造模之后植物鞘氨醇(phSM)、GM3均明显下降,艾司氯胺酮治疗增加了上述脂质小分子的水平(均P<0.05);与对照组相比,模型+生理盐水组磷酸肌酸(CerP)、硫苷脂水平下降,而艾司氯胺酮治疗并未影响上述脂质小分子的水平。(3)PFC鞘脂水平与行为学结果之间存在一定的相关性。CVS小鼠PFC总体鞘脂水平与旷场中心停留时间存在相关性(Pearson r=0.378 1,P<0.05),小分子phSM与旷场中心停留时间存在相关性(P<0.05);CVS小鼠PFC脑苷脂的小分子神经酰胺、CerP和CerG3水平与悬尾不动时间存在相关性(均P<0.05)。结论 艾司氯胺酮治疗可以改善CVS小鼠抑郁样行为,其作用可能与小鼠PFC鞘脂相对含量变化,尤其是鞘磷脂水平相关。